July 8, 2013

Uncanny Valley Getting Closer With Cell-Level Simulated Skin


 
Digital Avatars
Researchers using photographed samples of skin from people's chins, cheeks and foreheads at a resolution of about 10 micrometers, have created super-realistic simulated CGI skin with detail such that each skin cell spreads across only three pixels.




New research could further CGI graphics with simulated skin that is faithful down to the level of individual cells.

Creating realistic faces is one of the biggest challenges for CGI, in large part because skin's appearance is the sum of a complex interplay of tiny features and flaws. Get any of those factors wrong, and the CGI face comes out looking eerily wrong. "The renderings can only be as real as the input data," says Abhijeet Ghosh at Imperial College London. "And that's where we come in."

Uncanny Valley Getting Closer With Cell-Level Simulated Skin

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Ghosh and Paul Debevec of the University of Southern California (USC) and their colleagues had already developed a way to simulate light reflecting off human skin. It involves splitting the light into four rays: one that bounces off the epidermis and three that penetrate the skin to varying depths, scattering before being reflected.

The team have now massively cranked up the level of detail. Using a specially developed lighting system and camera, they photographed samples of skin from people's chins, cheeks and foreheads at a resolution of about 10 micrometres, so that each skin cell was spread across roughly three pixels. They then used the images to create a 3D model of skin and applied their light reflection technique to it. The result was CGI skin complete with minute structures like pores and microscopic wrinkles. Finally, they fed the CGI images to an algorithm that extended them to fill in an entire CGI face.

Usually, CGI uses a standard set of values for skin structure, says Ghosh. But for big-budget films, digital effects companies like Weta Digital – which used some of Ghosh and Debevec's techniques in the movie Avatar, for example – prefer to tailor skin textures to individuals. To create the blue-skinned Na'vi, for example, artists took surface details like moles and wrinkles and added them to the characters by hand. "In movies they zoom in to show that stuff off," says Ghosh, but the work is a slow process. Ghosh and Debevec's system, which Ghosh presented at the Games and Media Event at Imperial College London in May, could automate this level of customization.

CGI face

It's not only the entertainment industry that is eyeing this technology. In 2010, the cosmetics company Avon gave Ghosh funding to explore whether his digital skin could be used to simulate the application of different kinds of make-up. Other cosmetics firms have also showed interest in the idea. Ghosh thinks that one day we will have an app that offers a virtual try-before-you-buy service for make-up. "You would arrive at a kiosk and have your face scanned," he says. The software would then show you exactly what your skin would look like with, for example, a certain foundation applied, he says.

Next, he team at USC is working with games publisher Activision to try to find a way to bring these sort of high quality faces to games as soon as possible.


SOURCE  New Scientist

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